Conventionally, a variety of ingredients have been incorporated into a composition for external use, (hereinafter called an "external-use composition") such as a cosmetic composition, in accordance with the function to be realized in the external-use composition.
For example, an ultraviolet shielding agent is incorporated into an external-use composition in order to protect the skin from exposure to ultraviolet rays in sunlight, so as to prevent generation of age spots or freckles and skin aging, as well as to prevent generation of skin diseases such as skin cancer. When an external-use composition is processed into an emulsion such as milky lotion or cream or is stabilized, a surfactant is incorporated into the composition so as to emulsify or stabilize the composition.
Incorporation into an external-use composition of an ingredient suited for achieving an object enables provision of products matching a wide range of consumer needs; however, the incorporation may cause adverse effects.
Of the above examples, an external-use composition incorporated with an ultraviolet shielding agent tends to involve deteriorated sensation in use. Also, an external-use composition containing a surfactant in a large amount has been known to cause problems in safety and sensation in use.
A variety of measures have been investigated in attempts to solve the above-mentioned problems and to provide a higher quality, more reliable external-use composition.
Thus, a problem to be solved by the present invention is to find a key ingredient for effectively coping with the above problems, and to provide various external-use compositions in which the ingredient is used.